Finally, note that this analysis has focused only on the axion zero mode as a first step. Within the trapped mechanism the axion field self-interactions may become important whenever the axion is not close to the minimum. Non-linearities will induce the production of higher momentum axion quanta, i.e. axion fragmentation [1]}. The consequences of the fragmentation of the axion field within the trapped misalignment mechanism is left for a future work.
